Compare and suggest copy and paste the below command for further reference.
Have used it several time to make a Bootable Installer of Ventura and has worked fine.
Also, make sure the Application circled in below image have Full Disk Access
sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled
The Untitled in above command is the Name I have given the Destination Drive for the Bootable Installer
Plus, all the above is predicated upon the Full Version ( 12.xx GB ) of Ventura is located in the Applications Folder of this computer
